Piping Chocolate Embroidery?

I really don't feel like making buttercream tonight... I'm making ganache anyway so I was wondering if I make a white choc ganache if I can color it with gel color or if that would screw up the consistency.

Ideally I would like to do some red brush embroidery (would I have to add anything else for that?)over a ganache shell, but I can settle for plain piping if I can't so that.

You guys are always so helpful, and I appreciate anything you guys can do for me. ^-^